Scotland needs only 500 days to decide whether it wishes to remain part of the United Kingdom, Scottish Secretary Michael Moore is expected to say.

Mr Moore will tell the Scottish Liberal Democrat conference in Inverness that Scotland should be allowed to decide its future 500 days after the independence consultations close, rather than the 1,000-day plan announced by the SNP at its consultation launch.

Mr Moore said: "What I find frustrating is the Nationalists' determination to go slow. If Mr Salmond has confidence in his plans - if he really believes that Scotland will vote to leave the UK family - why does he drag his heels?

"In January, the SNP said Scots should wait nearly three years to determine their future. But we don't need 1,000 days to decide this crucial question. We can get this done in the 500 days that follow the consultations. In 500 days you can plan the poll, pass the law and hold the ballot.

"That is enough time for the Scottish people to hear the arguments, consider the evidence and express their view."

Mr Moore also highlighted concern voiced by major Scottish-based businesses recently about "the impact of uncertainty and delay" surrounding the referendum.

He said: "SSE, the Weir Group, Scottish Engineering. Every one of them has made the point that the uncertainty caused by a stalled referendum will impact on business decisions.

"And business decisions impact on employment in Scotland. Delay today kills jobs tomorrow. So, I say to the SNP: Quit stalling. Let's work together, get the wheels in motion, and allow the people to decide their future in 500 days."

The UK Government's consultation on Scotland's constitutional future closes on Friday, while the Scottish Government's own consultation will run until May 11.

This would put Mr Moore's preferred date of the referendum sometime around mid to late September 2013.